1. Field of the Invention
The present invention concerns a method to generate an image series for a 3D reconstruction using an x-ray image acquisition system that has an x-ray C-arm rotatable around a center point, the x-ray C-arm carrying an x-ray source and a flat panel detector, and which system has a movable patient table.
2. Description of the Prior Art and Related Subject Matter
A method of the above type is described in DE 10 2006 037 565.3, which was published after the application date of the present application.
A 3D reconstruction of an imaged region of a subject (in particular of a patient) can be derived when images are acquired from different directions. The 3D reconstruction in turn enables the calculation of slice images. In order to acquire the subject from different directions, an x-ray C-arm is conventionally moved in uniform angle intervals over an angle of 180°. An x-ray image (known as a projection) is acquired at each position defined by the angle intervals.
So that a region of interest of the subject can actually be reconstructed, it is necessary for the region to be completely imaged in each of the x-ray images. This is problematical when the region of interest is located beyond the center point of the subject (which typically forms the rotation center). For example, this is the case when the liver of a patient should be imaged. The region of interest that lies outside of the center point of the patient cannot define a new center point for a circular movement because otherwise the x-ray source or the x-ray detector would hit the patient.
In DE 10 2006 037 565.3 it is described to update a subject positioning device (thus a patient table) without collision in the horizontal direction so that a subject region of interest lies within a beam cone of an x-ray beam of the image acquisition system in each rotation angle of the x-ray C-arm in which an image acquisition ensues.
DE 10 2004 004 603 A1 discloses a simulation of a patient table in three dimensions for the purpose of compensation of movements of the patient on the patient table.
DE 10 2006 037 565.3 provides no details of how an updating of the patient table can ensue in multiple dimensions.